It has become generally accepted in the trade that containers which contain beverage and food products will have a label thereon. Many different systems are presently used to apply the labels to the containers. Some of these systems will apply the label to the container after it has been filled and sealed. Other systems utilize the prelabeled container which is then filled with the product and sealed before distribution.
The present invention is most closely associated with the systems that prelabel the containers before they are filled with a product.
Prior art systems which prelabel containers are known, and one such system which has received considerable acceptance is that disclosed in U.S. Pat. No. 3,802,942, issued to Amberg et al and assigned to the Assignee of the present application. This patent teaches the forming of labels from heat shrinkable plastic that is formed of a film-foam combination plastic that is fed in an oriented sheet form to a vacuum transfer head. The labels are preprinted and cut into lengths as they are received on the transfer head which then delivers the individual labels to a plural mandrel turret apparatus which winds the label into a complete sleeve on a mandrel and forms a seam where the ends overlap. Containers are simultaneously processed by being preheated and indexed over the sleeve supporting mandrels. The sleeves are telescopically assembled on the containers and then, together, are transported through a heat shrink tunnel. The plastic sleeve shrinks into snug surface fit with respect to the container.
As can be seen by reading the foregoing U.S. patent and U.S. Pat. No. 3,767,496, issued Oct. 23, 1973, which discloses the overall process that the apparatus of U.S. Pat. No. 3,802,942 will perform, the forming of a tightly conforming, heat shrunk label on a container, such as a glass bottle, is not a simple task. To prevent wrinkling of the label and consequent distortion in the graphics of the label, it is necessary to apply the label to the bottle in a careful manner. The ends of the label must come into registry so that the label will not seem to be askew. When the label is to be a heat-shrinkable plastic, the ends have to overlap and be firmly sealed together to form a seam that will withstand the stress that is produced when the label shrinks.
When it seemed desirable to make the labeled container without having the label formed into a seamed sleeve before applying it to the container, systems were designed to use the bottle or container itself as the mandrel and then wind the label about the bottle and seal the overlapped ends. This system has been disclosed in several recent U.S. Pat. No. 4,574,020, issued Mar. 4, 1986, to H. R. Fosnaught and assigned to the assignee of the present case.
In this patent there is disclosed apparatus and method for a high speed production line in which a container is wrapped with a film-foam plastic label comprising a foam polystyrene layer, there being a system for moving the leading edge of the label to the periphery of a rotating vacuum drum, means to apply a solvent to the underside of the foam layer to form finite areas, on the leading and trailing edges of the label, of a tacky solution. The solvent applied label is rapidly moved by the vacuum drum to a label-wrapping station where it is wrapped about the container with the finite areas of the solvent on the leading edge adhering to the container and the trailing edge overlapping and becoming sealed to the leading edge to form a complete vertical seam. After application of the label, the container is moved through a heat-applying oven to heat shrink the label into conformity with the underlying container.
The foregoing system, which utilizes a solvent to form the adhesive, has also been modified as taught in U.S. Pat. No. 4,662,965, issued May 5, 1987, to use a "hot melt" adhesive in place of the solvent to tack the leading edge of the label to a container and to firmly adhere the trailing edge to the leading edge to form a complete cylindrical sleeve that is then passed through the heat shrink oven.
The foregoing systems have proven useful; however, the solvent systems have presented problems in the plants where the solvent is being used because of the inherent nature of the vapors being present in the area surrounding the label-applicating machine. Exhaust systems are used to clear the atmosphere but these are costly to install and maintain. Also, the solvents are fairly expensive and in operation over a full day, a considerable quantity will be consumed. With the foregoing in view, the present invention is one which will overcome the problems found in the prior art systems.